1. Technical Field
The present invention relates to an oscillator, an electronic apparatus, and a moving object.
2. Related Art
The reference frequencies used for backbone lines such as a synchronous optical network (SONET) and a synchronous digital hierarchy (SDH) are required to correspond to different frequencies from each other. For this purpose, equipment related to a transmission device used for backbone lines is provided with a plurality of oscillators capable of respectively oscillating frequency signals different from each other, and is configured to select a certain oscillators to output a desired frequency signal, by a selection signal or the like from the outside.
For example, JP-A-2005-6130 discloses a two-frequency switching-type high-frequency quartz crystal oscillator including a first quartz crystal oscillation unit that outputs a first frequency signal, a second quartz crystal oscillation unit that outputs a second frequency signal, a first switch for supplying power to any one of the first quartz crystal oscillation unit and the second quartz crystal oscillation unit, by a selection signal from the outside, and a second switch that selects any one of the outputs of the first quartz crystal oscillation unit and the second quartz crystal oscillation unit, by a selection signal from the outside.
In this two-frequency switching-type high-frequency quartz crystal oscillator, the frequencies of the frequency signals which are output from the first quartz crystal oscillation unit and the second quartz crystal oscillation unit are adjusted, by controlling the capacitance of the variable-capacitance diode included in the first quartz crystal oscillation unit and the capacitance of the variable-capacitance diode included in the second quartz crystal oscillation unit by a frequency control voltage.
Further, the first quartz crystal oscillation unit further includes a resistor, and the characteristics of the above-described variable-capacitance diode and the resistor are appropriately selected, depending on the output frequency that is obtained by the first quartz crystal oscillation unit.
Similarly, the second quartz crystal oscillation unit also further includes a resistor, and the characteristics of the above-described variable-capacitance diode and the resistor are appropriately selected, depending on the output frequency that is obtained by the second quartz crystal oscillation unit.
In the two-frequency switching-type high-frequency quartz crystal oscillator of such a configuration, for example, as JP-A-2012-151773, it is conceivable to arrange both the first and second quartz crystal oscillation units on a single substrate.
However, if attempting to place (mount) two quartz crystal oscillation units on a single substrate, as described above, while reducing the size of the oscillator itself, there is a need to place two quartz crystal oscillation units in a limited region on the substrate, such that there is a limit to the degree of freedom in the design of the oscillator.
Therefore, there is a problem in that in particular, the output frequency of a quartz crystal oscillation unit (oscillator circuit) for outputting an output frequency of a higher frequency is unstable, depending on positions where the two quartz crystal oscillation units (oscillator circuit) are placed.